If the user prefers to record separate assemblages in separate database files, these can still be easily compared during the analytical process.
Data tables from one file can be linked to another. This is done by opening one of the database files, and selecting File | Get external data | Link Tables. Then choose the database file that will be compared with the one that is already open. The user will then have a choice of tables to be linked. Those starting with '*' contain most of the data, although for more information, see the Navigation and Structure page. These linked tables can then be queried in the usual way.
If a substantial amount of customisation has occurred, the comparison process may be hindered, as lookup tables may not have all definitions for all codes. However, comparison of the raw data can still take place, provided the user is aware of this.
An alternative method of comparison is to run queries externally, from Excel, using Data | Get External Data | New Database Query....
Additonal information is contained in Access' normal help files.